Picture frame



FIG. 1 is a front elevational view of a picture frame showing our new design, the side opposite being substantially flat, plain and unornamented;

FIG. 2 is a left side elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a picture frame, substantially as shown and described. 